Blow torch



D. A. LENK BLOW TORCH Jan. 9, 1940.

Filed April 9, 1937 Patented Jan. 9, 194

UNITED STATES BLOW TORCH David Allen Lenk, Newton, Mass.,`assignor toThe Lenk Mfg. Co., Newton Lower Falls,v Mass., a corporation ofMassachusetts Application April 9,19557, .serial No. 135,873

' 3 Claims.

This invention relates to a blow torch and more particularly to a typeof blow torch which, when once primed or preheated at itsvapor-generating and/or vapor-burning zones, continues to functionautomatically. Generally speaking, thistype. l

' of blow torch includes a reservoir for holding a pool of readilyvaporizable` liquid fuel, such as alcohol and gasoline, leading to avapor-generating tube rfrom which the fuel vapor is emitted underpressure into a burner tube wherein burning of the vapor takes place asa blast issuing from its outer end and projectible against the workv orsurface to be heated. There are various ways of feeding raw or liquidfuel from the pool held in the reservoir to the vapor-generating tube, acommon one of which involves using a wick that extends from a submergedposition in the pool to a position in the vapor-generating tube and thusserves to feed liquid fuel by capillarity from the pool to the internalwall of such tube which, when primed or preheated, progressivelygenerates fuel vapor under pressure from the liquid fuel progressivelybeing supplied thereto.

Heretofore, the practice has been to assemble the blow-torch elements soas to ensure the 1ocation of the upper end of the wick at apredetermined or fixed point within thevapor-generating tube, sinceproper location of such end is requisite for realizing desired fuelvvaporization while avoiding scorching or charring of such end. Whilethe use of a rope-like wick of more than sufficient cross sectional areanormally to occupy the cross section of the vapor-generating tube makesfor some frictional engagement by such wick of the internal tube wall,yet such engagement is not so firm or tight as to obviate dislodgment ofthe upper wick end, especially when the torch is roughly handled ordropped on a floor. It is possible to increase the cross-sectional intothe vapor-generating tube, but this expedient makes for diiculty ofassembly and detracts undesirably from the capillary quality of the wickwhere it is most needed, namely, where it is supposed to transmit liquidfuel lefficiently to the internal wall of the vapor-generating tube.-

The present invention affords simple and inexpensive means formaintaining the upper end of the wick in the desired xed orpredetermined position within the vapor-generating tube of a` blow torchof the type hereinbefore described while at the same time avoidingundesirable compression of the upper end portion of the wick in area ofthe wick and to squeeze it more tightly ycontact with the internal wallof such tube. The

means employed herein for such purpose may adV vantageously take theform of a Wire or equivalent elongated member possessed of rigidity orstiffness relative to the wick but capable of being flexed, wherefore,such wire may be associated 5 with the wick in such manner that itslower end is yin substantially non-dislodgable engagement with a portionof the internal wall of the reservoir, say, its bottom, and its upperend is inv sub-` stantially non-dislodgable engagement with the 10 upperend of the wick and holds it substantially fixed even when the blowtorch is dropped onto a floor or suflersother shocks in service tendingin the absence of such wire or equivalent member to cause undesirabledislodgment of the upper end 15 of the wick.l 1

With the foregoing and other features and objects in view, the instantinvention will now be described with particular reference to theaccompanying drawing, wherein,

Figure l is a largely vertical sectional view of a blow torch embodyingthe invention hereof.

Figure 2 depicts the wick in assembly with its holder ready forinsertion into the torch.

Figure 3 is an enlarged sectional detail through 25 the upper endportion of the vapor-generating tube with the wick and wick-holderproperly positioned therein.

Figure 4 is a view similar to Figure 3 showing a modied form ofwick-holder.

The torch shown in Figure 1 includes the `usual cylindrical fuelreservoir I0 whose bottom Il has a removable plug l2 for closing acentral opening I3 through which liquid fuel, such as alcohol orgasoline, may be introduced into the reservoirv 35 for repl'enishingfuel supply. rIhe bottom Il may be upwardly convex so that its skirtportion may together with the lower end portion of the cylindricalreservoir wall dene an annular pocket or recess I4 whereinto the lowerend portion of a wick-holder I5 may be directed so as to make frictionaland substantially non-dislodgable engagement with the internal walls ofthe reservoir, including the internal wall of the bottom Il.

Upstanding from the top of the reservoir is a vapor-generating tube I6whose lower end portion passes substantially vertically through abushing I7 having a flanged lower end `Ilot soldered or otherwisesutably fixed to the reservoir wall bounding the opening therein forreceiving the 50 lower end of the bushing. The lower end portion of thetube I6 may project slightly into the empty space Illa. normallymaintained above the fuel supply lb whose level is indicated in dashlines. The tube I6. may be frictionally held in thebushing l1 or besoldered or otherwise suitably secured thereto. The external wall of thebushing l1 is shown as carrying threaded thereon a nut I8 for clampingin position against the ilange I'Ia the upper end portion of a handle I9which is apertured to permit the passage of the tube I6 and the bushingil therethrough preparatory to the securement of the nut I8. The handleI9 may be formed of suitable strip metal and be of such curvature thatits lower end portion 19a comes close to the reservoir Wall.

The upper end portion of the vapor-generating tube I6, which may beinclined at any desired angle from the vertical, carries threaded uponits extremity a closure or cap 2B containing a tiny orice 2l throughwhich the fuel vapor generated in the tube i6 may issue as a jet.Threaded onto the external wall of the cap 20 may be the usual burner orcombustion tube 22 whose wall contains a number of apertures 23 forallowing atmospheric air to enter into the burner tube for promotingrcomplete combustion of the fuel vapor. The vapor-generating tube iB maybe primed or preheated in any suitable way, as by igniting a primingcharge of liquid fuel placed in an annular dish 24 resting on the upperend of the bushing Il and slidable on the tube i6.

The wick Z5 for feeding liquid fuel by capillarity from the pool lb tothe internal wall of "-f the vapor-generating tube I6 may consist of aloose bundle of parallel strands or rovings of cotton having verylittle, if any, twist so as to exercise maximum capillary action. Thebundle of rovings or rope-like wick material may, pursuant to theinvention hereof, be assembled preparatory to its insertion in the torchwith a wick-holder i5 consisting essentially of flexible wire whoseupper end portion is in the form of a hook or eye i5a through which thebundle of rovings is threaded, as shown best in Figure 2, to provide adoubled-over wick whose ends terminate at or extend beyond the lower endof the wire. The wick and holder assembly thus prepared may be readilyinserted into the upper end of the tube iE and the wire pushed downalong with the wick until its lower end has found its way into thecorner or pocket I4. If desired, the ends of the wick may be suicientlybeyond the lower end of the wire l5 to form an accumulation on thebottom of the reservoir. By using wire I5 of the appropriate character,no trouble is had in causing such wire to assume a curvature such thatits lower end is trapped frictionally in the pocket I4, but, should anydiffrculty be encountered in this regard, it is easy to prebend orpreshape the wire so that its lower end immediately seeks out the cornerill as the wickA and holder assembly is being pushed down through thetube I6 into the reservoir. The length of the wire l5 is such that onceits lower end is brought to rest in the corner Ill, its upper end 15alocates the upper end of the wick properly within the Vapor-generatingtube i6; and,

inasmuch as the upper end of the wick is thus fixed in a predetermineddesirable position, it

does not tend to become charred by reason of being dislodged throughshock to a position too close to the burner tube or to generate vaporinefficiently or irregularly by reason of being accidentally displacedto a position too remote from the burner tube.

Ordinary steel wire, such as so-called semispring steel wire of about 18or somewhat greater gauge, is typical of the material of constructionsatisfactory for the wick-holder hereof. In lieu of steel wire, it ispossible to employ semi-hard brass wire and even ductile metal wire orribbon, provided that the ductility of the metal wire or ribbon is notso great that it will flex or shift its position in the torch when thetorch is roughly handled or suffers impact or shock. In some instances,it may be desirable to use as the wickholding element multiply wire ofappropriate stiffness or rigidity, for instance, twisted multiply wiresuch as is used for cleaning the stem of a smokers pipe. Such a twistedmultiply element Si? appears in Figure 4 as two intertwisted wires whosesuccessive twists or convolutions contain locked therebetween fiberbunches 3l in such density that the exterior aspect is that of apractically continuous fuzzy-surfaced fibrous body. The wick 25 is shownas being looped over the top end of such a multiply wire member 3D,which top end serves to stop downward displacement of the wick.; and, byvirtue of the frictional engagement between the wick and the largeaggregate external fibrous surface of the fiber bunches 3i as well aswith the internal wall of the burner tube upward displacement of thewick is also practically precluded. It might be noted fm'ther that thecapillary action of the ber bunches 3i augments that of the wick properso as to ensure the desired capillary feed of liquid fuel from the poolin the reservoir to the vapor-generating tube.

it might be noted that the temperatiue developed in the burner tube wallby continued combustion of such vaporizable fuels as alcohol andgasoline may be in the order of magnitude of about 16300 to 200 F. Atemperature gradient exists inwardly from the outer or hottest end ofthe burner tube and thence downwardly along the Vapor-generating tube,in consequence of which the upper end of the moist wick may be incontact with the internal tube wall surface at sufciently elevatedtemperature, say, about 600 to 800 F., to volatilize or fiash the liquidfuel practically instantly but yet not so hot as to induce sensiblechalring of the wick. The wickholder hereof ensures the maintenance ofsuch desirable location of the upper end of the wick and, being also agood heat conductor, promotes preheating and vaporization of the liquidfuel as it is diffusing by capillarity upwardly through the wicking. Thewick-holder hereof is not only simple and inexpensive but does not alteressentially the method of assembling the torch elements or addsignificantly to the cost of the finished torch.

So far as concerns certain subject mattei', this application is acontinuation-in-part of my application Serial No. 46,522, filed October2a, 1935.

I claim:

l. In a blow torch, the combination with a reservoir for holding a poolof vaporizable liquid fuel, a vapor-generating tube whose inner endopens into the upper portion of' said reservoir, a vapor'- burner tubewhose inner end communicates with said vapor-generating tube, and a wickwhich is of loose, rope-like form and extends from. a

submerged position in said pool to a positiorn' while substantiallyuncompressed in said vapor- .generating tube; of an elongated memberwhich 1s possessed of rigidity relative to said wick and extends alongwith said wick from said reservoir able engagement with the upper end ofsaid wick, whereby the upper end of said wick is held by said .member insubstantially fixed lposition in said vaporgenerating tube even whensaid blow 'torch is dropped or undergoes other shock in service tendingin the labsence of said member to cause undesirable dislodgment of theupper end of said wiok.- f y 2. In ablow torch, the combination with areservoir forholding `a pool of vaporizable liquid fuel, avapor-generating tube whose inner end opens in the upper lportion ofsaid reservoir, a Vapor-burner tube whose inner end communi- 'Cates Withsaid vapor-generating tube, and a Wick which is of loose, rope-like formand extends from ya submerged position in said pool to a position, whilesubstantially uncompressed, -in said vapor-generating tube; of anelongated member which .is possessed o rigidity relative to said wickbut is capable of being iiexed and extends in ii'exed curved conditionalong with said wick from said reservoir into said vapor-generatingtube; the lower end of said member being trapped frictionally in apocket deiined between the skirt portion of the internal bottom Wall andthe lower end portion of the internal side wall of said reservoir andthe lower end of said member existing in substantiallynon-dislodgable,frictional engagement with the internal bottom Wall of said reservoir;and the upper end of said member existing in substantiallynon-dislodgable engagement with the upperk end of said Wick, whereby theupper end of said Wick is held by said mem,-

ber in substantially fixed position in said vapor-y generating tube evenwhen said blow torch is dropped or undergoes othershock in servicetending in the absence of said member to cause undesirable dislodgmentof the upper end of said wick.

In a blow torch, the combination with a reservoir for holding a pool ofvaporizable liquid fuel, a vapor-generating tube whose inner end opensin the upper portion of said reservoir, a vapor-burner tube whose innerend communi- Cates with said vapor-generating tube, and a Wick which isof loose, rope-like form and extends from a submerged position in saidpool to a position, while substantially uncompressed, in saidvapor-generating tube; of a wire which is possessed of rigidity relativelto said wick but is capable of being exed and extends in iiexed curvedcondition along with said wick from said reservoir into saidvapor-generating tube, the lower end of said Wire existing. insubstantially nendislodgable, frietionalv engagement with the internalbottom wall of said reservoir and the upper end portion of said wirebeing in the form of a hook encompassing the upper end portion of saidWick, whereby the upper end of said wick is held by said wire insubstantially xed position in said vapor-generating tube even when saidblow torch is dropped or undergoes other shock in service tending in theabsenee'of said wire to oauseundesirable dislodgment of the upper end ofsaid wick. i l y 4 DAVID ALLEN LENK.

